If the client is gone, and the session finished, no need to
return. The async handler can use this information to avoid
unnecessary work and exit earlier.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/qapi/qmp/dispatch.h |  8 ++++++++
 qapi/qmp-dispatch.c         | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/include/qapi/qmp/dispatch.h b/include/qapi/qmp/dispatch.h
index e426317346..6ee82371a2 100644
--- a/include/qapi/qmp/dispatch.h
+++ b/include/qapi/qmp/dispatch.h
@@ -91,6 +91,14 @@ void qmp_return_free(QmpReturn *qret);
 void qmp_return(QmpReturn *qret, QObject *rsp);
 void qmp_return_error(QmpReturn *qret, Error *err);
 
+/*
+ * @qmp_return_is_cancelled:
+ *
+ * Return true if the QmpReturn is cancelled, and free the QmpReturn
+ * in this case.
+ */
+bool qmp_return_is_cancelled(QmpReturn *qret);
+
 void qmp_register_command(QmpCommandList *cmds, const char *name,
                           QmpCommandFunc *fn, QmpCommandOptions options);
 void qmp_register_async_command(QmpCommandList *cmds, const char *name,
diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
index f7d9931734..99f5128170 100644
--- a/qapi/qmp-dispatch.c
+++ b/qapi/qmp-dispatch.c
@@ -63,6 +63,16 @@ void qmp_return_free(QmpReturn *qret)
     }
 }
 
+bool qmp_return_is_cancelled(QmpReturn *qret)
+{
+    if (!qret->session) {
+        qmp_return_free(qret);
+        return true;
+    }
+
+    return false;
+}
+
 static void qmp_return_orderly(QmpReturn *qret)
 {
     QmpSession *session = qret->session;
-- 
2.17.0.rc1.1.g4c4f2b46a3